Title: Simple ribbon moves and primeness of knots
Speaker: Tatsuya Tsukamoto (Osaka Institute of Technology)
Abstract: We define and study local moves on links, called simple ribbon moves. Each simple ribbon move on a link L is a special kind of a band sum of L and trivial links. We study when a simple ribbon move changes a link type, and if a knot which can be transformed into the trivial knot by one simple ribbon move is prime. This is a joint work with Kazuaki Kobayashi and Tetsuo Shibuya.